Anonymous wrote:It is not your job to sell her ticket.
Ordinarily I would agree but I think OP is being obtuse here. It's not that hard to re-sell concert tickets in this day and age -- you post them online and especially if you are far enough in advance, you can usually recoup all or most of your costs.
What I think happened is that OP *offered* to find a buyer for the second ticket because she still wanted to go, and since her friend had bought the tickets and was in possession of them, her friend handed them over so OP could do that. But instead of finding a buyer, OP just found another friend she wanted to go with and told the original friend she "couldn't find a buyer."
I think the friend would have just tried to resell her own ticket, but OP likely insisted on having it so she could try to find someone she wanted to go with.